The present invention relates to colorless or near colorless compounds useful for marking or tagging petroleum fuels. It also pertains to a reagent useful in developing color and fluorescence of base-extractable markers.
A marker is a substance which can be used to tag petroleum products for subsequent detection. The marker is dissolved in a liquid to be identified, then subsequently detected by performing a simple physical or chemical test on the tagged liquid. Markers are sometimes used by government to ensure that the appropriate tax has been paid on particular grades of fuel. Oil companies also mark their products to help identify those who have diluted or altered their products. These companies often go to great expense to make sure their branded petroleum products meet certain specifications regarding volatility and octane number, for example, as well as to provide their petroleum products with effective additive packages containing detergents and other components Consumers rely upon the product names and quality designations to assure that the product being purchased is the quality desired.
It is possible for gasoline dealers to increase profits by selling an inferior product at the price consumers are willing to pay for a high quality branded or designated product. Higher profits can also be made simply by diluting the branded product with an inferior product. Policing dealers who substitute one product for another or blend branded products with inferior products is difficult in the case of gasoline because the blended products will qualitatively display the presence of each component in the branded products. The key ingredients of the branded products are generally present in such low levels that quantitative analysis to detect dilution with an inferior product is very difficult, time consuming and expensive.
Marker systems for fuels and other petroleum products have been suggested but various drawbacks have existed which have hindered their effectiveness. Many, for instance, lose their color over time, making them too difficult to detect after storage. In addition, reagents used to develop the color of markers often are difficult to handle or present disposal problems. Furthermore, some marking agents partition into water. This causes the markers to loose effectiveness when storage occurs in tanks that contain some water.
The present invention provides markers which are invisible in liquid petroleum products but that provide a distinctive fluorescence and/or color when extracted from the petroleum product with an appropriate developing reagent. The reagents used to develop the fluorescence are themselves easy to handle and dispose of.